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#pragma once

#include "stdafx.h"

// Programmable Interrupt Controller Emulator

//

// This class emulates some of the functionality of the interrupt

// controller. Edge sensing on the interrupt inputs is not currently

// supported. The edge sensing on the clock interrupts is emulated

// by resetting the interrupt input when the PIC recieves the

// command to acknowledge the edge sensitive interrupt and only

// driving the interrupt signal true by the timer. The timers

// effectively act like pulse generators which provide only a

// positive transition to the clock signal. The negative 

// transition is supplied when the interrupt is acknowledged.

// In the real system the clock generator provides a square wave

// output for the interrupts so edge sensing is necessary.

// It's faked out so that from the perspective of the BIOS

// software it looks the same.

extern clsSystem system1;

class clsPIC : public clsDevice

{

public:

        bool enables[16];

        bool edges[16];         // edge sensitive

        bool irq30Hz;

        bool irq1024Hz;

        bool irqKeyboard;

        bool irqUart;

        bool irq;

        bool nmi;

        unsigned int vecno;

        clsPIC(void);

        void Reset();

        bool IsSelected(unsigned int ad) {

                return ((ad & 0xFFFFFFC0)==0xFFDC0FC0);

        };

        unsigned int Read(unsigned int ad);

        void Write(unsigned int ad, unsigned int dat, unsigned int mask);

        void Step(void);

};